From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Davidlohr Bueso , Andi Kleen , Rik van Riel , Andrew Morton , Linus Torvalds , Mike Galbraith Subject: [ 36/69] ipc,msg: introduce lockless functions to obtain the ipc object Date: Wed, 16 Oct 2013 10:44:45 -0700 Message-Id: <20131016174317.287427785@linuxfoundation.org> In-Reply-To: <20131016174312.844154919@linuxfoundation.org> References: <20131016174312.844154919@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davidlohr Bueso commit a5001a0d9768568de5d613c3b3a5b9c7721299da upstream. Add msq_obtain_object() and msq_obtain_object_check(), which will allow us to get the ipc object without acquiring the lock. Just as with semaphores, these functions are basically wrappers around ipc_obtain_object*(). Signed-off-by: Davidlohr Bueso Cc: Andi Kleen Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman --- ipc/msg.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) --- a/ipc/msg.c +++ b/ipc/msg.c @@ -166,6 +166,27 @@ static inline struct msg_queue *msg_lock return container_of(ipcp, struct msg_queue, q_perm); } +static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct msg_queue, q_perm); +} + +static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct msg_queue, q_perm); +} + static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) { ipc_rmid(&msg_ids(ns), &s->q_perm);